Assembly of sight glass and electrode means for mounting on a liquid container



Nov. 4, 1958 M. J. DE LEONARDIS 2,359,310

ASSEMBLY OF SIGHT GLASS AND ELECTRODE MEANS FOR MOUNTING ON A LIQUID CONTAINER Original Filed Aug. 15. 1954 I N VEN TOR: M07454 Jfle/swwww;

i Patented N om 4,,

This application is a division of my copending application Serial No. 449,592, August 13, 1954, now abandoned, in which is disclosed means for controlling the liquid level within a liquid container, such for example as the water space of a boiler of a steam or hot water heating system, or a tank, and for preventing fuel from being fed to a boiler or ignited therein when the water level is below a predetermined limit.

The control means disclosed in said copending application include a pair of spaced electrodes between which a small electric current passes when said electrodes are bridged by liquid, it being specified that one of the electrodes may be the grounded, electrically conductive wall of the container itself.

This application is directed to an assembly which may be readily attached to, and operatively mounted on, any liquid container in communication with liquid within the container to conveniently provide the electrode means between which a circuit may be completed when liquid reaches a predetermined level within the container.

An object of the invention is to provide a novel combination of sight glass and electrode means of the above mentioned kind.

Another object of the invention is to provide an assembly of the above mentioned kind including means extending into the sight glass and serving, when the assembly is assembled on a container wall, as an extension of the wall.

The invention will best be understood if the following description is read in connection with the drawings in which:

Figure 1 is a side elevation partly broken away and in section showing an embodiment of the invention.

Figure 2 is a horizontal section taken on the line 22 of Fig. 1; and

Figure 3 is a horizontal section taken on the line 3-3 of Fig. l, partly broken away.

As shown in Figure l the assembly comprises a tubular member preferably formed of glass and having at least a transparent midportion. The ends of member 10 are received in the tubular nipples 16 and 18 projecting from the coupling and valve members 12 and 14 respectively which are preferably made of brass. Each of said memhers is adapted to be attached to a boiler or tank and provide communication between tube 10 and the liquid space within the boiler or tank.

Lower member 12 comprises a tubular portion 22 one end 2211 of which is externally threaded for insertion in the aperture 26 in the wall 24 of a boiler, tank, or the like. Wall 24 is also bored to provide the aperture 28 in which member 14 is inserted. The latter is similar to member 12, except it does not have a drain cock, and so is not separately described.

The end 22b of member 22 is externally threaded to receive the cap 30 having a central opening 31 through which extends the valve stem 32, the outer end of which has thereon the handle 33, and the inner end of which is reduced in diameter to extend loosely into the throat of 2 :1 v the annular plug 23 within portion 22a and to providethe conicalshoulder 34 which seats on the corresponding sloping outer face portion 35 of plug 23. I

' The coupling and valve members 12 andf14arenormally'open to provide liquid within the sight glass'to indicate the level, of liquid within the container on which the sight glass is assembled. Upper member, 14. is similar to the lower member 12 except'that it does not have the drain cock. Both members maybe of'standardjcon struction." h Projecting through the wallof the'transparentportion 10 of the sight glass assembly are the electrode assemblies 36 and 38 each of whicl'rcomprises, an electrode 40;

which is a wide thin conductive member, and a conductor. V '42 extending through the wallof the tube and connected at its inner end to the member 40. Within tube 10, spaced from said electrode assemblies but extending past them both is the long strip of metal 43, preferably. corrosion resisting steel, which is a third electrode and is supported within the tube 10, as by angle brace member 52, and

has an end 43a extending beyond one end of the tube V 10 and bent to contact conductive member 22 which in turn is in contact with and electrically connected to the a threaded bore provided in the electrodes 40, and the interior surface of the container wall 24.

Each of the conductors 42 is preferably screwed into The lower end of tube 10 which is received in the nipple 16 abuts against the coil spring 19, which rests against shoulder 16a of said nipple. The ends of tube 10 are held in place in the nipples 16 and 18 by means of screw caps 20 which have annular heads through which the ends of tube 10 extend, and the internally threaded tubular skirt portions of said caps engage the externally threaded nipples 16 and 18 respectively. Between the heads of said caps and the outer ends of said nipples 16 and 18 respectively the packing rings 21 are provided. The brace member 52 serves to support the elongated electrode 43 within the tube and to position the bent over end 43a to make a dependable contact with the conductive tubular nipple portion 16 of valve assembily 12. Said portion 16 being a continuation of conductive member 22 is in contact with the wall 24 as soon as portion 22a ofthe valve assembly is screwed into the boiler wall. Spring 19 coacts with brace 52 to provide a dependable contact between the elongated electrode 43 and said portion 16 of the valve assembly, the springacting to press the bent over end portion 43a upwardly while brace member 52 presses the electrode outwardly against the metal wall 16 of the valve assembly 12. Spring 19 being itself a conductor provides a further electrical contact between the bent over end 43a of electrode 43 and the conductive valve and coupling member 12.

The boiler or tank of which wall 24 is a part being grounded an electric circuit is completed throughlead theaboye mentioned objects are embodied together with many practical advantages.

What I claim is: V 1.,-A sight glass assembly comprising electrically con ductiye tubular end portions, and a transarent inter mediatefiortiom; threeelctrodes disposed Within said sight glass and conductors extending through the wall of extending through the wall of glass and conductor means said intermediate portion. from one of said electrodes',the

second of said electrodes extending from a point within thcfsight glass and adjacent to the other electrode into contact with an electrically conductive tubular end portion, the distance between'said electrodes being such as will permit electric current to flow from one to another through water entering said sight glass fronrtheiboiIe iahibridging said electrodes.

References Cited in the filefof this patent a 7 UNITED STATES PATENTS 654,631 Hays July 31,1900 2,719,876 Cain; Oct. 4, 1955 

